Please help...

My son has bad gas. Sometimes when he's eating he will stop and squirm and it's like passing gas hurts him! Could this be a food intolerance problem? He is 7 weeks old. I ebf and he also chokes sometimes while eating and a couple times when he spit up while laying flat right after he ate. I have an over supply and have been block feeding to help this issue. I'm not sure if this is reflux, intolerance or my oversupply. Occasionally he will also have a semi green bm- but it's usually mixed with yellow seedy. Any advice is appreciated!!!